0:01

Hi, I'm Greya, and this is The

0:03

Climate Question, where we ask simply, what

0:06

on earth can we do about climate change? Podcasts

0:11

from the BBC World Service are supported

0:13

by advertising. Where

0:18

to be a woman is the podcast celebrating

0:20

the best of women's wellbeing. Listen

0:23

now wherever you get your BBC podcasts.

0:30

Welcome to The Climate Question from the

0:33

BBC World Service. This

0:35

week, listeners like me are taking over the

0:37

show with our questions. I'm

0:39

your host, Greya Jackson, and

0:41

you listeners are back with

0:43

your questions about climate change.

0:48

I would like to know if there

0:50

are any expected geological effects of climate

0:52

change. How much of global

0:54

warming is caused by the heat given

0:57

off by a human body? I

0:59

want to know how bad are the corridors of

1:01

the environment. Answers to

1:03

those and more coming right up. Three

1:09

familiar faces or voices are here with

1:11

me to tackle your climate questions. I

1:13

have Justin Rowland, the BBC's climate editor.

1:16

Hello, Jason. We have

1:18

Akshat Rathi, Bloomberg's senior climate reporter

1:20

and author of Climate Capitalism. Hello.

1:23

Hi. And Tamsin Edwards, professor

1:25

of climate change in King's College, London.

1:28

Hello, Tamsin. Hi there. How

1:30

are we all? What have we all been up to?

1:32

Oh, it's an exciting week because my book is

1:34

out in the US this week. Congratulations.

1:36

That's exciting. Get the

1:38

bucket early. Tamsin,

1:43

what have you been up to at work? I

1:45

have been obsessing about a big analysis I've been

1:47

working on predicting sea level rise to the year

1:49

2300, bringing together

1:51

lots of different computer model predictions with machine

1:53

learning, trying to get the numbers out for

1:55

a deadline, basically. Wow. That's

1:58

so interesting. I think it's really Interesting to look. Beyond

2:00

Twenty one hundred which the nominee where people

2:02

stop because of Easy once you got stuck

2:04

in carbon an atmosphere is gonna go in

2:06

changing things for some time exactly. Twenty One

2:08

hundred? Not that long away when we sought to plan

2:10

infrastructure and so on. So we really need. To

2:12

their feather Exactly. I've been. I've

2:15

I've been doing a very interesting

2:17

story this weight looking at the

2:19

battle for these metallic know jewels

2:21

on the deep sea floor which

2:23

saw the mine as kramer essential

2:25

for the new of renewable transition

2:27

but the green activists say will

2:30

destroy a pristine environment. sorcery, interesting

2:32

conflict that. We have you been taking sides?

2:34

Us that. Here in London hair in lower

2:36

than and man nothing. To

2:39

say that says sites the huge of is quite

2:41

different. A state I think his last time we

2:44

spoke to you like building a wet us

2:46

a sin in South America or something. Money

2:48

that's right s actually have to say sitting

2:50

at my laptop is the norm the at

2:52

going. Up a mountain and city is very much

2:54

not the norm and I made me to recover

2:56

stuff that arctic laptop work is such a set

2:58

of those are those services on us In truth

3:00

Mississippi you access my get to travel for work

3:03

which is nice to be able to go and

3:05

see where the solutions are being built by not

3:07

to the bottom of the ocean cause I don't

3:09

know is human conflict with that that. Wasn't

3:12

a sense of you've been looking at. So

3:14

I'm obsessed with how to

3:16

make steel using only electricity

3:18

and producing know emissions. Wow.

3:21

Okay, and and casinos a big

3:23

contributor seven percent. Of. Global greenhouse

3:25

gas emissions more than aviation and

3:27

sipping com mind And okay, so

3:29

it's important. Let skates on a

3:32

that to us fast listener question since

3:34

this is Alison at program. Hello!

3:37

My name is Carla and I'm from

3:39

Oregon in the Usa. I would like

3:41

to know thera any expectancy, illogical effects

3:44

of climate. Change such as

3:46

changes in earthquake patterns or

3:48

volcano eruptions. That might result

3:50

from changes in sea. Level or other

3:52

climate related changes. that

3:55

some that and when i first had this

3:57

question i thought really and i looked into

3:59

and it's true, just explain how that

4:01

can be the case. It sounds a bit bonkers doesn't

4:03

it, but if you think about it lots of things

4:05

that are affected by climate change on the planet are

4:08

heavy, by which I mean ice

4:10

and water. So if you do lose

4:13

ice when glaciers retreat for example it kind

4:15

of reduces the stress on the Earth's crust

4:17

and you can get more earthquakes and maybe

4:20

even more volcanic activity, this has been seen

4:22

in a study for Iceland about 5000 years

4:24

ago, and the same with water as well.

4:26

So in the Himalayas they see changes and

4:29

just tiny changes in earthquakes, micro seismicity that

4:31

goes with the seasonal cycles of the monsoon.

4:33

So when there's lots of heavy rain falling

4:36

on the Earth it sort of dampens the

4:38

seismicity and then when the monsoons stop they

4:40

see a peak. Wow okay and

4:42

you say micro, I mean how much is

4:44

it even a point on the Richter scale?

4:46

Basically this is small scale stuff. We have

4:49

seen much bigger changes in the past of

4:51

course because over the Earth's history we've seen

4:53

really big changes in climate over really long

4:55

periods of time. So you do get bigger

4:58

changes in the past but at the moment

5:00

it's smaller. Actually in Greenland they also see

5:02

maybe some more earthquakes I think in the

5:04

summer when there's less ice and that seems

5:06

to be increasing as well. And could the

5:09

opposite be true? You talk about more rainfall,

5:11

less rainfall, what about in conditions like drought

5:13

might there also be implications there? Yeah good question,

5:15

I was thinking about this and there's a kind

5:17

of indirect effect of climate change so when we

5:19

get droughts and we have to think about our

5:21

water resources humans tend to do things like extract

5:23

from groundwater like we see this in the USA,

5:26

fill up reservoirs and drain them again

5:28

and again those changes can cause small earthquakes

5:30

actually. But those changes in ice do have other

5:33

big impacts don't they? There's something, you're

5:35

going to correct me if I'm wrong,

5:37

but isostatic rebound? So when the ice

5:39

melts the Earth, you know it kind

5:42

of melts in places like the Himalayas,

5:44

the Earth begins to change its position

5:46

because the weight's been lifted off it.

5:48

And interestingly a lot of the kind

5:50

of sea level rise that we see

5:52

is actually land sinking as a result

5:54

of the changes in ice

5:57

around the globe. Yeah that's Right? So that's

5:59

what I meant when I said that. When you

6:01

get... the guy is retreating and you lose that

6:03

big heavy weight, you will sort of living in

6:05

that dumpling. You get that earth lifting up and

6:07

in some places the earth going down instead of

6:09

counterbalance the. Certain places I'd Bangladesh A

6:11

lot of the sea level rises in Bangladesh

6:13

is actually a function of i started rebound

6:15

rather than rising sea levels. Yeah, we want

6:17

a combination of yeah, We have the up

6:19

less than the humans and then we also

6:22

have the extraction of resources. All of these

6:24

things can make sea level where exactly the

6:26

other think we may. this program about Greenland

6:28

and the other thing I found absolutely fascinating

6:30

about this with that because the I see

6:33

is so big their Greenland has a gravitational

6:35

pulling effect on the a sense and as

6:37

it melts it's releasing that water and that

6:39

also causes sea level to drop in Greenland

6:42

but then actually feather way it causes the

6:44

sea levels to rise which I just found

6:46

anything exactly where actually more affected by melting.

6:48

Of the antarctic ice sheet up here, in in

6:51

the Uk and and the rest. of Europe

6:53

rather than from Greenland which is

6:55

close by because because. Basically, as

6:57

he lays eyes, we lose the kind

6:59

of gravitational pull off the ice on

7:01

the water. The water kind of fools

7:03

away. So close to Greenland, the sea

7:05

level drops because it's actually kind of

7:07

not. Succeeded by a gravity not brought

7:09

him. Yeah, and it sort of distributes around the rest

7:12

of the world. But sorry on this. There

7:14

is another fight. isn't there that the spinning

7:16

of the earth draws the ocean water into

7:18

the tropics so years Erotically, the topics are

7:20

disproportionately affected by melting of both polls on

7:23

they because the water draws into the middle

7:25

of the ocean, there's all kinds of fact

7:27

that the temperature of the water. Makes

7:29

an impact. So when you get things like

7:32

warm spots, el ninos, ocean currents, eight or

7:34

Change has really high salary cap. I have

7:36

theory. Really told a lie. Ample

7:38

Average: The level of regional sea

7:41

level is wrong. Really reality. Next.

7:43

We have a listener, Danielle. He says,

7:45

I'm in China where we have the

7:47

most electric cars around the world and

7:50

the number is still increasing very very

7:52

fast. Our electricity grid is under pressure,

7:54

we drop oil and we pick up

7:57

batteries instead. His question is, do we

7:59

have a. No power plants to

8:01

support. Such a high demand of

8:03

electricity. Accept. Such.

8:05

I thought about this rarely rights that the

8:08

energy transition has been going on for some

8:10

time, but the train as easy transition has

8:12

been two decades in the making and their

8:14

entire reason was to try and move away

8:16

from fossil fuels. not really about carbon, they

8:18

just didn't want to in board so much

8:20

oil that was not available in China. they

8:22

had to go to Saudi Arabia to get

8:24

it. Last. Year China

8:26

alone installed enough solar

8:28

panels. That the entire

8:30

United States has done. In History

8:32

and he did that in one

8:35

year. So, electricity isn't really a

8:37

problem that China has to deal

8:39

with when it comes to whether

8:41

it can get enough power. To.

8:43

Get electric cars moving. I

8:45

mean maybe what Daniels are firing to is

8:47

the fact that China has experienced blackouts over

8:49

the last. He submits has an app that

8:51

it has. And that's partly to do with

8:53

the sheer amount of changes it is

8:55

making to the grid and has to

8:57

figure out how to manage it well.

8:59

And that's the reason why. Cool continues

9:01

to play a big role in China's

9:04

transition, right? They are still building the

9:06

most number of coal power plants in

9:08

the world. With sons, we're doing all

9:10

the solar in the world I hadn't

9:12

so much call a damned wind rims.

9:14

of course I. Was

9:16

that is actually like. For a these in

9:18

China, it's spectacular. So the first gold

9:20

a date set in recent years was

9:23

to reach twenty percent of all new

9:25

car sales by Twenty Twenty Five. Being

9:27

he these, well, they crossed that last

9:29

year round. and now the nouveau was

9:32

supposed to be forty percent by twenty

9:34

thirty. They're. Going to cross that

9:36

this year actually. It's not just electric vehicles

9:38

in a way that we might think them for

9:40

with as batty two and three wheeled vehicles are

9:42

really taking off and a for hims to cats

9:44

so on the trajectory. To Net Zero you're going

9:47

to require all these solutions that need to

9:49

go at pace. None of them are working

9:51

at base rate because Net Zero so hard.

9:53

The only one that is working is to

9:55

Nc Wheeler Electric Legal. System Let's leave

9:57

on the next question. It kind of relates to act.

10:00

been talking about. So wrap your ears around this. Hello,

10:03

my name is Bill and I'm

10:05

from Philadelphia, USA. I wanted to

10:07

know, can there be significant growth

10:09

and investment in renewable energy capacity

10:11

and is it still be true

10:13

that the greenhouse gas emissions and

10:15

fossil energy extraction is increasing? Justin.

10:18

Yeah, this is kind of corrective

10:20

to actually, you know, optimistic picture

10:22

of China. Yeah, unfortunately, it is

10:24

true. We are seeing significant growth

10:26

in renewables and simultaneously we can

10:29

see growth in fossil fuel emissions.

10:31

I mean, there has been a

10:33

massive growth in renewable investment. There's

10:35

a great stat from the International

10:37

Energy Agency, which is kind of

10:39

the world's energy watchdog. And

10:41

it found that for every dollar invested in oil

10:44

and gas, we're seeing

10:46

$1.7 invested in renewables.

10:48

Great news, you know, renewables overtaking,

10:50

it would seem oil and

10:52

gas. But, you know, energy demand still

10:55

continues to increase. And unfortunately, electricity is

10:57

just 20% of total energy demand. And

10:59

you think about places like India and

11:01

Africa, there's a huge amount of development

11:03

happening in those countries. People who didn't

11:05

have things like, you know, motorbikes or

11:08

cars or have the opportunities to heat

11:10

their home or even, for example, to

11:12

take their first holiday flight and they're

11:14

beginning to do all of those things

11:16

and increase their energy use. So

11:18

we are seeing an increased use of energy. I mean,

11:20

I was going to go on, I don't know if

11:23

we've got time, I was going to go and talk

11:25

about the Gevron's Paradox, which is this economist who looked

11:27

at the British Industrial Revolution. He was like, hold on

11:29

a second, all the machines we're using are getting so

11:31

much better at using energy. But energy demand continues to

11:33

rise. So his paradox was why have it so much

11:36

more efficient and we're using more energy. And if you

11:38

think about it, we use more energy because the more

11:40

efficient it gets to use energy, the more we can

11:42

do with it and the more we can do with

11:44

it, the more stuff we can make, the more we

11:46

can sell. So it's in our interest, it's kind of

11:48

incentive to use more energy. I was just going to say,

11:52

Gevron's Paradox. Yes, you're absolutely right.

11:54

Good. Well, thank you. Yeah, he's

11:57

absolutely right. Welcome

12:03

aboard the BBC World Service. I'm

12:05

your pilot. I'm

12:26

the I've

12:29

been listening to the episodes on biofuel

12:32

and doing a bit of my own

12:34

research. As you said

12:43

on your show, one of the biggest

12:45

problems with biofuel is the amount of

12:47

land needed to produce enough corn, for

12:49

example. I agree this

12:51

is a serious roadblock, but I wonder

12:53

if vertical farming could be the solution.

12:56

Okay, quick 101 on biofuels. It's a

12:58

fuel with a similar chemical composition to

13:00

fossil fuels like petrol or gasoline, but

13:03

it's extracted from crops like corn and it

13:05

could be used instead of jet fuel,

13:07

for instance, in airplanes. Has anyone been to

13:09

a vegetable farm before? I wonder. Yeah,

13:12

I went to a couple of them actually. One just outside

13:14

Paris, a startup called Jungle

13:16

and then one in Singapore called

13:18

GrowGrace. When you're inside, you

13:20

really can't tell whether you're outside Paris or

13:23

outside Singapore. It's the same atmosphere because the

13:25

temperature is controlled, the humidity is controlled and

13:27

there are these lights that look purple-ish. It

13:30

feels like you're in a disco. It feels

13:32

like you're in a spaceship is what I

13:34

found when I went here. Yep,

13:36

yep. They sometimes play music to the crops. You

13:38

know, you do feel like you're in a disco.

13:41

No, they don't. You're joking. No, seriously, they

13:43

play music to the crops. Is there a

13:45

scientific reason for playing music? Yeah, they think,

13:47

at least in GrowGrace's case, they think that

13:49

that particular species of lettuce grew better because

13:51

they were playing music. No, no, no, no.

13:53

I'm not saying it scientifically. I mean, for

13:55

anyone who's not, I'm not saying it scientifically.

14:00

never been to one. How would

14:02

you describe it? It typically

14:04

is, it's a huge shed essentially. It could be

14:06

in an office block or it could just be

14:08

in an industrial farm and it is

14:11

rows and racks of just

14:13

herbs most of the time

14:15

or green salad, right, lettuce

14:18

that's growing in rows and rows with

14:20

different lighting depending on which stage of

14:22

growth it is in or which stage

14:25

of day light it

14:27

is in because you know if you're in

14:29

Paris you might go through winter and summer

14:31

but the plants inside that vertical farm they

14:33

do not. It's summer always, you get the best

14:35

weather. Hold on so you've got to I mean

14:38

so it's not using natural sunlight it's using

14:40

light so then there obviously is a huge

14:42

energy to buy but no the lights are

14:44

LEDs right which is quite a development. So

14:47

the entire cell is you're going to use

14:49

just energy mostly to run this thing because

14:51

the water gets recycled you do add some

14:53

nutrients obviously but it is

14:56

temperature controlled it is light

14:59

controlled and it is power

15:01

hungry and so vertical farms have been

15:03

really struggling right now with where power

15:05

prices are and some of them have

15:07

gone bankrupt. Well

15:10

let's just circle back to Dante's question

15:12

which is more about land use right

15:14

and as Akshat is saying you know

15:16

because they're stacked in trays like bookshelves,

15:18

shells after shelves, it can save a

15:20

lot of space and I looked at

15:22

whether you can grow biocrops

15:24

in these situations and you can some

15:26

varieties are perfectly suitable for vertical land

15:28

so in answer to your question Dante

15:30

yes and as Akshat said you can

15:32

grow them year round and because the

15:34

environment is so controlled we could grow

15:36

them bigger with less inputs like water

15:39

and fertilizer. Except the energy. Yes I

15:41

was about to say so there is a

15:43

big butt here and that is they're really

15:45

expensive to set up for one And

15:47

also really expensive to run because of this

15:50

high energy requirement. and that might have a

15:52

big climate cost as well depending on where

15:54

that energy comes from, right? If it's renewables,

15:56

fine, if it's coming from fossil fuels, less

15:58

good. The talk about

16:01

farms were gonna go over to

16:03

another relevant listener question that slants

16:05

in the and bucks hello announced

16:07

Nikkei and I often get home

16:09

at about half an avocado. Our

16:11

environments. I don't know how

16:13

about they aren't passing out across. That.

16:15

Are they really are attachments? Oh it's everybody

16:17

to spot for. They just. Supposed to

16:19

face unsustainable farming. Now

16:21

I'm a big enough about the holidays is

16:24

questions They somehow Thompson you're nodding along a

16:26

certain frequencies not us for Axa. I mean

16:28

as I've demonstrated, I'm so let's see. Been

16:30

listening that one's be giving up their avocados

16:33

and the five as climate zones so that

16:35

keep us on our list. So tell us

16:37

what's the cost of avocados if there. Is.

16:39

One I also don't want to give up

16:42

on avocados. I had never had one until

16:44

I moved to this country at the age

16:46

of twenty one because it's not something that

16:48

you know got imported into in yet he's

16:50

at that time and so the biggest cost.

16:53

On. Carbon footprint for food is

16:55

what you eat, not where it comes

16:57

from. The transporter missions that are touched.

16:59

Two things are coming from abroad. You

17:01

know they might come from South America.

17:03

They might sometimes even come from Australia.

17:06

Or a tiny fraction. And so if you

17:08

really want to cut your emissions, Look

17:10

at these and other me products

17:12

and reduce that seed mouse. Makeup

17:14

generally lost in the percent of the a

17:17

full carbon. Footprint Of Food. That

17:19

said, there are some seats flown in like

17:21

of fruits right? and strawberries like highly. Paris

17:23

for once. it doesn't apply to everything, but

17:25

it's generally is a good rule of thumb.

17:27

I it's the food itself, not where it

17:29

comes. From to have known as a bullshit

17:31

on boats and that's fine and melons and

17:34

stuff like that but if you have to

17:36

suffer as he say are displayed in and

17:38

it will gets kind of pretty obvious which

17:40

free they are if you look at them

17:43

then made do have a very high speed

17:45

ball frame or caviar in on those kinds

17:47

of things which people can afford the aboard

17:49

by and getting it's a slow name sometimes

17:51

isn't the issue with avocados that they use

17:54

tons of water in normally very dry places

17:56

as but like almonds in California that just

17:58

not really a very. Soon. crop for

18:00

a dry place. Right, and eating local for

18:02

other reasons like supporting local farmers, supporting communities,

18:05

those are very good reasons to eat local

18:07

but also the seasonal benefits of eating local

18:09

and so you're supporting not extractive farming that

18:11

consumes too much water in other places. And

18:13

at the risk of sounding like a total

18:15

downer, isn't the issue health-wise with avocados? They've

18:18

got loads of cholesterol in them. No, it's

18:20

good fats. No, no, no. I was going

18:22

to say, I'm going to chime in. I've

18:24

read a lot of good things about the

18:26

fats in avocado. I'm like, I'm fine. Do

18:29

you hate avocados? I'm saying. I hate

18:31

avocados. You're the

18:33

one picking hulls today instead of me. We roll

18:35

reverse. The nice thing about diet actually is it's

18:37

one of those things that really shows the example

18:39

of co-benefits because a diet that's

18:41

good for the planet is generally good for

18:44

humans as well. So lots of fruit and

18:46

veg, lots of beans and lentils, stuff

18:48

like that. So really kind of plant-based, doesn't

18:51

mean no meat or dairy if that's what you

18:53

want to have, but minimizing those as much as

18:55

possible, saving them more for a treat or special

18:57

occasion, good quality, this kind of thing. And actually

18:59

what's good for the planet tends to be good

19:01

for us too. We don't talk about the co-benefits,

19:03

but it's not just things like diet. I mean,

19:05

we were talking about EVs earlier. There are huge

19:07

benefits in that there's not lots

19:09

of tailpipe emissions that people then breathe

19:12

in, our children then breathe in. It has

19:14

huge benefits. Exactly. We've moved away

19:16

from that conversation of thinking about climate change

19:18

being, about giving things up and having a

19:20

hard life and hair-shirt environmentalism they

19:22

used to call it. And then

19:25

much more about what's the world we want to create?

19:27

What are all the ways that we're going to make

19:29

it better that also benefit the climate? Thank you, Tamsin.

19:32

Our next question is from someone who

19:34

wants to remain anonymous. They say, is

19:36

it possible for climate change to be

19:38

reversed? Justin another difficult one for

19:41

you. Yeah, okay, a really tough question.

19:43

That is a really big question as

19:45

well. Look, in theory, yes, we

19:47

could reverse climate change. And if

19:49

you think about it, it's quite simple. Climate

19:52

change is caused by the greenhouse gases. We've

19:54

pumped into the atmosphere. We can take them

19:56

out. The world's going to not just cool

19:58

less, but will actually cool down. and some

20:01

of the gas is a quite easy to

20:03

deal with and been positive. Hear me that

20:05

I can bury the sample size of the

20:07

atmosphere for twenty years. It's about thirty percent

20:09

of the human induced climate change that we've

20:11

had so far. Such a big component of

20:13

it's there is background me say this produced

20:15

naturally but if we can reduce the amount

20:17

that human beings admit that we could begin

20:19

to slow climate change with us. little bit

20:21

more tricky when you come to the main

20:23

climate gas which is carbon dioxide cover nice

20:25

had stays in the atmosphere you be to

20:28

get the exact figure for returns and but.

20:30

For centuries, sometimes for millennia for thousands

20:32

of years. So it hangs around for

20:34

a long time. So the question is,

20:36

really can we take.com and outside out

20:38

of the atmosphere? There are ways to

20:41

do it. but the certainly not developed

20:43

a scowl at the moment. And the

20:45

other thing about them as with so

20:47

many technologies associate with climate change is

20:49

they are really expensive yes at the

20:51

moment. but they do have self really

20:54

fundamental challenges because of the nature of

20:56

the toilet. Are these technologies you're describing?

20:58

The literal machines that for an air

21:00

and they have a processed scripts. the

21:02

common outside out and and you can store.

21:05

That's another more controversial wife doing it

21:07

is using biomass trees as they grow of

21:09

a c absorb come outside of he'd

21:11

been them and and capture the carbon

21:13

dioxide from the trees. that it's negative. so

21:15

long as you grow more tree so

21:17

socially it's possible but it's really hard

21:19

now. Something. About

21:21

I would. I give us us. I would actually pull

21:24

back a little bit to the beginning as well because he

21:26

said climate change can be river as I'm going to pick

21:28

your phone that to that's nice. We would say that global.

21:30

Warming could be renounced. and

21:32

actually the law and i really care about

21:34

this because i study the i seats in

21:37

the classes and actually the impacts of global

21:39

warming another was the white earth's climate change

21:41

only parts of that could be reversed sits

21:43

just legal insist and so many wait know

21:45

the difference in climate change and global warming

21:47

exactly exactly and i think we know we

21:49

sell us and use them interchangeably and i

21:52

do myself and it's it's really understandable because

21:54

in many ways we do things with them

21:56

as meaning the same things the when i

21:58

say global warming i mean the temperature

22:00

of the air and the oceans going up.

22:02

You know, we talk about one and a

22:04

half degrees of warming, two degrees of warming.

22:07

But then that has impacts on

22:09

the whole planet. And that is

22:11

what we would call the wider

22:13

climate change or the climate impacts.

22:15

So, for example, melting of mountain

22:17

grasses or of the big ice

22:19

sheets of Greenland and Antarctica, I

22:21

study these. And these are things

22:23

that we really think would not

22:25

be reversible. And actually, the last

22:27

report of the Intergovernmental Panel on Climate

22:29

Change said that these effects would last

22:31

for hundreds to thousands of years. And

22:34

that's very much not reversible. I'll try

22:36

and finish on a more positive note,

22:38

though. I wish. Yeah, I because it's

22:40

a really it's a tough one for us to sort of

22:42

even think about, you know, to even understand what that means.

22:44

But Arctic sea ice is something

22:46

that has been decreasing. So that's the floating

22:49

ice over the top of the northern

22:51

regions of the planet. That would also

22:53

regrow, we think, if we called the

22:55

planet back down. But a huge challenge

22:57

is with being able to cool that planet back

22:59

down quickly as opposed to

23:01

slowly as we've heard. We need to move

23:03

on to our final question. And again, this

23:05

is another facet of climate change I had

23:07

never thought about. In Tamsin, it's going to

23:09

involve you doing some back of the envelope

23:11

calculations. How's your maths? Good. It's

23:14

very, very back of the envelope. OK, well,

23:16

your exam question is about to be set.

23:18

I see you've got your pen ready. Let's

23:21

hear it. Hello, my

23:23

name is Tony from Australia, and

23:25

I would like to know how much

23:27

of global warming is caused by the

23:29

heat given off by a human body?

23:32

OK, so how much heat is given

23:34

off by the human body? And then you times

23:36

that by what, eight billion and you

23:38

know, what's your what's your own one? And what's your

23:40

work? So when I was looking

23:42

at this before today, I found

23:45

a really pleasing fact, which is that the

23:47

average human gives off about 100 watts

23:49

of heat, which is about what

23:52

an old style light bulb. So

23:55

like nothing, really, that. Well, it's a nice kind

23:57

of image, isn't it? We're all here as

23:59

our little light bulb. walking around the planet.

24:01

So if you think of that, you know, multiply

24:03

that by how many days in a year

24:05

and how many humans, you get to about

24:07

300 billion watts. So that's quite a

24:09

lot. But it's actually not that

24:12

big in the grand scheme of things. You

24:14

know, the planet has a lot of energy.

24:16

For example, well, energy production is 600 billion

24:18

billion watts. Oh,

24:21

wow. Okay. It's not billion. Billion, billion.

24:23

So a lot more. And

24:25

I think, but the thing I really want to, I like, I

24:27

love questions like this, you know, we all like to kind of,

24:29

you know, what if, what does

24:32

that mean? What does that do? And

24:34

it's really important to be able to sit down and

24:36

think how that works. But I'll just pick up on

24:38

the sort of how much of global warming

24:40

is caused by, because I think that's the key

24:42

thing. It's not the maps of how much heat

24:45

humans give out like all

24:47

humans. It's about what actually is

24:49

global warming, what's it what's causing

24:52

it. And that we really need

24:54

to step back to the kind of space

24:56

scale, the solar systems go on. We look

24:58

at the planet from a distance. And what

25:00

matters is how much energy is going in

25:02

from the sun, and how much energy comes

25:04

out is radiated out to space as heat.

25:06

And they're not changing that big picture

25:08

of how much heat is in the

25:10

system, if you like the whole planetary

25:12

system. And that's what controls global warming.

25:15

I feel like we should have set up a

25:17

thermometer gauge at the beginning of this recording and

25:19

see how much it has raised by four humans

25:21

producing heat. Exactly. Because that's

25:23

what's tipping what we call the energy balance of

25:26

the planet. And that's what matters. Whereas our

25:28

human heat is just part of the little

25:30

fluctuations of moving heat around the planet, if

25:32

you like. But if we don't

25:34

want to think about the global, what probably has

25:36

happened in this room is that

25:39

the CO2 levels have gone

25:41

up, right? So outside, it's

25:43

about 400 parts per million for 20 parts per million

25:45

right now. In here, it probably

25:47

has doubled in an hour. And if

25:49

there's not good ventilation, that can happen.

25:52

You know, 1000 people, 1000 PPM, we

25:54

can survive up to 2000 PPM and

25:56

it's fine. But our brains

25:58

start to slow down. Now you

26:00

don't. Do you think we've got

26:02

less? Are you saying AXAT with some

26:04

less insightful? Join the course.

26:06

There you go. I think that's what he's

26:08

saying. Well,

26:11

that seems like the perfect place to end it,

26:13

AXAT, given that we're all getting a little bit

26:15

less insightful. Thank you so much, G3,

26:17

for joining us. I really appreciate it. Cheers. Thank

26:20

you. Thank you. This

26:22

was fun. Thanks. That was

26:24

the BBC's climate editor, Justin Rollat,

26:27

climate change scientist, Professor Tamsin Edwards,

26:29

and AXAT Rathy, senior climate reporter

26:31

for Bloomberg. The production team this

26:34

week were Osman Uqbal, Sophie Eastor,

26:36

Brenda Brown, Graham Puddyfoot and Tom

26:38

Brignall. Don't forget you can

26:40

send us your climate questions and I'll get one

26:43

of these three, or if you're a

26:45

lucky me, to answer it. Email

26:47

theclimatequestion at bbc.com.

26:50

I'll see you next week. It

27:01

all started with me asking my friends and

27:03

family to write letters to my daughter, Coco,

27:06

sharing their experiences and giving her advice

27:08

for her life ahead. The

27:10

idea blossomed into Dear Daughter from

27:12

the BBC World Service. The

27:14

podcast where, with the help of your

27:17

letters, I'm creating a handbook to life

27:19

full of advice for daughters everywhere. Listen

27:22

now by searching for Dear Daughter

27:24

wherever you get your BBC podcasts. Dear

27:27

Daughter. Lucy

27:58

must have his due. Tune

28:01

in every week for the latest anime updates and

28:03

possibly a few debates. I

28:05

remember, what was that? Say what

28:07

you're gonna say and I'll circle back. You

28:10

can listen to Crunchyroll Presents, the anime effect,

28:13

every Friday wherever you get your podcasts. And

28:15

watch full video episodes on Crunchyroll or the

28:18

Crunchyroll YouTube channel.